1. Field of the Invention
The present invention relates generally to apparatus for the chemical treatment of water and, more particularly, to apparatus for injecting two or more incompatible chemicals into a water stream to be treated while advancing within a vessel into which only one opening is available. Throughout this disclosure, the term "water" will be taken to include liquid H.sub.2 O as well as water in its vaporous form, that is, steam.
2. Description of the Prior Art
A number of patents are definitive of the present state of the art of water treatment. For example, as disclosed in U.S. Pat. No. 5,514,284 to Uban et al., ozone generation tubes are positioned upstream of filtration beds and downstream of the point where water treatment chemicals are added to the water. By properly arranging the tubes in an array, the tubes will serve as a static mixer Water that passes through the array is agitated, thereby mixing the additive chemicals into the water prior to filtration.
U.S. Pat. No. 5,387,249 to Wiecorek discloses a self-contained chemical injection device for use with toilets which assures that the chemical never comes into contact with the other components in the tank of a toilet bowl, resulting in a more efficient and environmentally safe chemical treatment process for the toilet bowl water.
U.S. Pat. No. 4,286,900 to Sugimote et al. discloses a device for precisely injecting dual chemical fluids for mixing in the ground while preventing earth and sand around the injection device from flowing back through the injection port or ports into the interior of the injection device.
U.S. Pat. No. 5,277,250 to Dela discloses an injector for injecting a liquid treatment chemical into a moving body of liquid in a pipe. The injector includes an elongated hollow quill member having a stem portion of a length to span substantially the inside diameter of the pipe. The stem portion is provided along substantially its entire length with a substantially uniform set of jet openings for injecting the cross section of the body of liquid with a number of chemical treatment jet streams so that the cross section of the body of liquid is treated uniformly across its diametrical cross section.
Traditionally several water treatment chemicals are diluted in a mix tank and fed over a period of time, typically one day. Feed is to a moving bulk stream in the system to be treated. This stream is typically water or steam. Injection of mixture of chemicals is by a single quill into the center of the moving stream.
Water treatment chemicals must be diluted to about 10% with water when fed in this manner. If mixed neat, that is, undiluted, precipitation of one or more of the components is likely to occur. Fittings to accept the injection quill are typically welded into the vessel or piping.
There is a growing trend to eliminate the makedown or dilution step and simply feed each chemical neat directly from the storage tank. This is a safety as well as a labor saving practice. Since two chemical products cannot be mixed neat, each one must have a separate feed or an injection point into the system. This currently requires taking the system off-line and welding a new injection fitting into the system for each additional chemical to be fed.
It was with knowledge of the foregoing state of the technology that the present invention has been conceived and is now reduced to practice.